Portable surface-treating machine with improved platen-mounting construction

ABSTRACT

An electrically-driven portable surface-treating machine having the motor and means driven thereby for oscillating a platen mounted within a clam shell housing. The oscillatable platen is connected to the housing through securement to a plurality of resilient posts connected to the housing. The posts are formed with flanges which are retained within recesses formed transversely in the housing and there are pairs of such posts at respective ends of the housing, a flange of each pair of posts being in abutting relationship.

1 51 Aug. 26, 1975 United States Patent 1191 Klebe, Jr. et al.

[ PORTABLE SURFACE-TREATING MACHINE WITH IMPROVED PLATEN-MOUNTINGCONSTRUCTION P i Exa iner-Donald G. Kelly Inventors: Elmer C. Klebe,Jr., Easley;

Attorney, Agent, or FirmMarshall J. Breen; Chester Timothy Looper,PiCkBnsy both f A. Williams, J11; Harold Weinstein SC.

ABSTRACT [73] Assignee: The Singer Company, New York,

An electrically-driven portable surface-treating ma- Filedi 1974 chinehaving the motor and means driven thereby for oscillating a platenmounted within a clam shell hous- 21 Appl. No.: 442,518

ing. The oscillatable platen is connected to the housing throughsecurement to a plurality of resilient posts connected to the housing.The posts are formed with flanges which are retained within recessesformed 4 m0 3 m2 m I m m2" .l C St Um NH 55 Field Of Search-m 51/170 170170 R transversely inf-the housing and there are pairs of such posts atrespective ends of the housing, a flange of each pair of posts being inabutting relationship.

[56] References Cited UNITED STATES PATENTS 2,885,833 5 1959 51 170 MT 2Clams 5 Drawmg Flgures PATENTED IQYB PORTABLE SURFACE-TREATING MACHINEWITH IMPROVED PLATEN-MOUNTING CONSTRUCTION BACKGROUND OF THE INVENTIONIt has been knwon heretofore to provide electricallydriven portablesurface-treating machines such as sanders, polishers, buffers and thelike with an oscillatable platen which is connected to the housing ofthe machine through securement to a plurality of resilient posts.Generally, pairs of such posts are positioned at opposed ends of themachine. The housing for such ma chines is frequently formed by a pairof complementary mating halves which are detachably secured along thelongitudinal axis of the machine. Such housings, are known in the art asbeing of the clam shell type.

In order to impart the desired motion of the platen of such a machine ashereinbefore referred to it has been found desirable to connect theplaten to a plurality of such resilient posts. However, to insure properinitial seating and avoid subsequent accidental displacement of theposts during normal operation of the machine, as well as to facilitateintegration of the platen subassembly with the housing, variousexpedients have been adopted. One such prior construction utilizes aspecially deformed back plate for the platen subassembly in combinationwith a bracket in order to locate the base flanges of the resilientposts with respect to the platen and permanently affix them in place. Aspacer member is used at the top of adjacent posts which posts also actin concert with a specially designed groove and annular tongue in thehousing for positioning of the upper segments of the posts. Thus, therehas been a long standing need for improving the constructionalarrangement by which the platen is secured to the housing through theuse of the resilient posts.

SUMMARY OF THE INVENTION It is one object of the invention to provide aelectrically driven portable surface-treating machine in which anoscillatable platen is supported by a plurality of resilient postswithout any substantial risk of unintended post displacement and withoutrequiring the use of a separate spacer element, which overcomes theprior art deficiencies and is simple, economical and reliable.

It is another object of the invention to provide an electrically drivenportable orbital sander having an oscillatable platen s ubassembly whichcan more easily be mounted to a clam shell housing and which uses postswhich are self locking in pairs within the clam shell housing.

Other objects and advantages of the invention will become readilyapparent upon reading the following description of the invention.

The present invention thus, provides in an electrically-driven portablesurface-treating machine in which the motor and means driven thereby foroscillating a platen are mounted within a longitudinally divided clamshell housing and said platen is connected to said housing by beingsecured to a plurality of resilient posts connected to said housing, theimprovement which comprises:

a. transversely, extending recesses formed in the ends of one of saidplaten and housing;

b. a plurality of resilient posts each of which i vided at one endthereof with a flange dimensioned t fit within said recesses to securesaid one end of th post therewithin;

c. said posts being provided at the other end thereof with a lockingelement cooperable with a locking element associated with the other ofsaid platen and housing to secure said other ends of said posts thereto;

d. an oscillatable platen connected to an end of each of said resilientposts; and

e. said posts being positioned between said housing and platen in pairswith a first post of each pair secured to said platen and housing on oneside of the longitudinal division in said housing and the second postsof each pair secured to said platen and housing on the other side of thelongitudinal division in said housing such that the contiguous end facesof the flanges of each of said first and second posts are in abuttingrelationship.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the invention may befully comprehended it will now be described, by way of example, withreference to the accompanying drawings in which:

FIG. 1 is a perspective view of a surface-treating machine embodying theinvention;

FIG. 2 is a side elevational view in larger scale, with the housingpartly broken away and partly in section, of the machine shown in FIG.1;

FIG. 3 is a sectional view of the machine shown in FIG. 2 taken alongline 33 thereof;

FIG. 4 is a bottom plan view, in smaller scale, of the resilient poststructure shown in FIG. 3 taken along 44 thereof; and

FIG. 5 is an exploded view, partly in section, of an end of the housingwith one resilient post in position and the other post of the pairremoved from the housing.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1 and 2, thereis shown an electri- Cally-driven portable surface-treating machine 8which, as depicted, is a sander. The machine is provided with a clamshell housing 10 comprising a pair of complementary halves 11, 12 whichare detachably connected by fastening means such as carriage bolts 13which are desirably spaced at intervals which will assure close matingof the shells l1, 12. The machine is provided with slots 14 for theentry of cooling air for the motor and with at least one slot 15 for theexit of the air from the machine. A handle 16 is desirably formedintegral with the housing 10. An electric switch l7,is mounted in thehandle 16 whereby the operator can energize the motor M through switchconnection with a source of electric power (not shown). A forwardlypositioned hand support 18 is also provided, preferably formed integralwith the housing, so that the machine may be grasped by the operatorwith both hands for easy manual control. An oscillatable platensub-assembly 19 is connected to the housing at the bottom thereof. Itwill be understood, of course, that the platen assembly can be socontrolled as to provide for reciprocatory and/or orbital movement asdesired.

FIG. 2 shows that the motor M is mounted within the housing and the'armature shaft 20 thereof is furnished with a fan 21 to induce coolingair through slots 14. A pinion 22 is formed at the lower end of theshaft 20. A

3 reduction gear mechanism 23 is seated within the housing and i sprovided with a gear 24 engageable with the pinion22. The gear 24 ismounted on a shaft 24a which rotates with gear 24 and has an eccentriccrank 25 formed at its lower end to connect into the eccentri- {llydrive a bearing bracket 26 which is mounted on Wile back plate 27 of theplaten sub-assembly to thus impart the oscillatory motion to the platen19.

As is depicted more clearly in FIGS. 3 and 5, the platen subassembly 19comprises a resilient pad 28 which is bonded to the rigid back platemember 27. Both the pad and back plate are preferably essentially planarexcept for the terminal longitudinally extending edges of the back platewhich are turned up along at least a substantial portion of theirlengths. The platen sub-assembly 19 in its preferred form is rectangularin plan view as can be seen most clearly from FIG. 1. The pad and backplate are provided adjacent each of their four corners with throughapertures 30, 31 for a purpose to be hereinafter set forth. A pluralityof resilient posts 32, desirably formed of hard rubber or other suitableelastomeric material, extend from the housing and rest upon the uppersurface of the back plate 27 of the platen sub-assembly 19. Each of theposts 32 is provided with a central bore which desirably accommodates amolded in place insert 33 which is adapted to threadedly receivefastening means such as screw 34 in order to operatively connect theplaten assembly to the posts 32. As shown in FIG. 3, screws 34 areinserted through apertures 30, 31 of the pad 28 and back plate 27,respectively, and screwed into inserts 33 to releaseably lock the platensub-assembly 19 to the bottoms of the posts 32 at each corner of thehousing.

The housing 10 is, as aforestated, of clam shell type. It is provided ateach end with a transversely extending, generally U-shaped recess 35dimensioned to receive a top flange 36 which is formed on each of posts32 as hereinafter described. As shown most clearly in FIGS. 2, 3 and 5,a pair of posts are positioned at each end of the housing 10, each suchpair comprising first and second posts which are spaced from each otherand are located on opposite sides of the longitudinally split housing10. Each such post 32 is provided with a top flange 36 of generallyrectangular configuration. The thickness of the flange is such that uponassembly with the housing the flange will be accepted within the recess35. Preferably a sliding fit between the flange and internal walls ofthe recess is provided although the height of the recess may be taperedslightly from the opening at the longitudinal split in the housing tothe outer sidewall of the housing to enhance retention of the flangewithin the recess. It will also be appreciated that by forming therecess with a tapered height the insertion of the flange into the recessduring assembly will be facilitated, thereby contributing to massproduction manufacture of the machine.

The resilient posts 32 are formed with a columnar body portion 32a,preferably of cylindrical configuration, and with a flange section 36 atone extremity of the body portion 32a. One end of the flange preferablybegins at the face of the underlying wall of body 32a and the flangeextends substantially beyond the face of the opposed sidewall of body32a. The overall length of the flange is such that when both halves ofthe housing are brought together into mated relationship, the end facesof the flanges of each respective pair of posts adjacent thelongitudinal centerline of the housing are brought into abuttingrelationship. Such cooperative dimensioning of the lengths of theabutting flanges aids in self-locking of the upper segments of the posts32 within the recesses. This self locking feature may also be achievedby dimensioning the length of each flange such that it is slightlylonger than the transverse extent of the recess in which it is received.Thus, as shown by areas a and b in FIG. 4, a portion of each flange iscaused to undergo a relatively small degree of stress upon mating of thehousing halves. Such constructions for the abutting flanges serves tomaintain the upper segments of the posts in their designed positionswithin the housing and thereby provide the desired degree of stabilityfor the mounting of the platen. Of course, it will be appreciated thatone of the flanges may be formed slightly smaller in length than thelength of the recess whereas its abutting flange may be formed with alength sufficiently great so that the desired abutment betweencontiguous flanges nevertheless occurs.

As may be clearly seen from FIGS. 2 and 3 of the drawings the posts 32are desirably positioned one in each corner of the housing. The flanges36 of the post pairs at each end of the housing on opposite sides of thelongitudinal split in the housing extend a substantial distance beyondthe body of the post towards the inner portion of the housing. Thelength of the flanges are preferably approximately twice the dimensionof the post body 320 although such proportion is by no means critical.Thus, during operation of the machine the upper and lower segments ofthe posts 32 are maintained in relatively stable and fixed relationshiprelative to the housing 10 and platen 19 to which they are secured. Yetthe intermediate region of the body 32a is afforded the degree ofresiliency necessary to impart the desired oscillatory motion to theplaten.

From the foregoing it will be seen that applicant has provided anextremely simple construction for securing the oscillatable platen tothe housing by means of the plurality of resilient posts. Nevertheless,the resilient posts are maintained within the housing at thepredetermined designed locations by virtue of the particular flangeconstruction retained within the transverse recess in the housing andthrough use of the fastening means at the other end of the posts.

Numerous alterations of the structure herein disclosed will suggestthemselves to those skilled in the art. However, it is to be understoodthat the present disclosure relates to a preferred embodiment of theinvention which is for purposes of illustration only and not to beconstrued as a limitation of the invention. All such modifications whichdo not depart from the spirit of the invention are intended to beincluded within the scope of the appended claims.

Having thus set forth the nature of the invention, what is claimedherein is:

1. In an electrically-driven portable surface-treating machine in whichthe motor and means driven thereby for oscillating a platen are mountedwithin a longitudinally divided clam shell housing and said platen isconnected to said housing by being secured to a plurality of resilientposts connected to said housing, the improvement which comprises:

a. transversely extending recesses formed in the opposite ends of thehousing,

b. a plurality of resilient posts each of which is provided at one endthereof with a flange dimensioned to fit within said recesses to securesaid one end of the post therewithin,

c. said posts being provided at the other end thereof with a lockingelement cooperable with a locking element associated with the other ofsaid platen and housing to secure said other ends of said posts thereto,

cl. an oscillatable platen connected to an end of each of said resilientposts,

e. said posts being positioned between said housing and platen in pairswith a first post of each pair secured to said platen and housing on oneside of the longitudinal division in said housing and the second post ofeach pair secured to said platen and housing on the other side of thelongitudinal division in said housing, and

f. each of said posts is located in a comer of said housing with theflange of each post in each said pair of posts extending towards theflange of the other posts in the pair a predetermined distance beyondthe columnar body of the post such that the contiguous end faces of theflanges of each of said first and second posts are in abuttingrelationship, and the lengths of the abutting flanges are sufficientlygreat to stress the terminal portion of each such flange in the regionof the abutting end faces upon assembly of the divided halves of thehousing.

2. A portable sanding tool comprising:

a. a clam shell housing having a pair of housing halves interconnectedto each other along a longitudinal split in said housing,

b. an electric motor mounted in the housing,

c. drive means mounted in the housing to be powered by the motor,

d. a pair of spaced recesses formed in each housing halve to extendtransversely of the longitudinal split,

e. each pair of recesses in one housing halve formed in alignment withthe pair of recesses in the other housing halve,

f. a plurality of resilient posts adapted to extend from a positionadjacent each comer of the housing,

g. a platen connected to each of the resilient posts, and operativelyconnected to be driven by the drive means,

h. each of the resilient posts having an integrally formed flangeextending a predetermined distance outwardly therefrom to define an endface thereon, and

. each flange insertable into one of the recesses of the housing halvesto be independently held therein and having the end face of the flangeextending toward the longitudinal split whereby on assembly of thehousing halves the adjacent end faces to come into engagement with eachother forcing the resilient posts to be locked into their respectivecomer positions.

1. In an electrically-driven portable surface-treating machine in whichthe motor and means driven thereby for oscillating a platen are mountedwithin a longitudinally divided clam shell housing and said platen isconnected to said housing by being secured to a plurality of resilientposts connected to said housing, the improvement which comprises: a.transversely extending recesses formed in the opposite ends of thehousing, b. a plurality of resilient posts each of which is provided atone end thereof with a flange dimensioned to fit within said recesses tosecure said one end of the post therewithin, c. said posts beingprovided at the other end thereof with a locking element cooperable witha locking element associated with the other of said platen and housingto secure said other ends of said posts thereto, d. an oscillatableplaten connected to an end of each of said resilient posts, e. saidposts being positioned between said housing and platen in pairs with afirst post of each pair secured to said platen and housing on one sideof the longitudinal division in said housing and the second post of eachpair secured to said platen and housing on the other side of thelongitudinal division in said housing, and f. each of said posts islocated in a corner of said housing with the flange of each post in eachsaid pair of posts extending towards the flange of the other posts inthe pair a predetermined distance beyond the columnar body of the postsuch that the contiguous end faces of the flanges of each of said firstand second posts are in abutting relationship, and the lengths of theabutting flanges are sufficiently great to stress the terminal portionof each such flange in the region of the abutting end faces uponassembly of the divided halves of the housing.
 2. A portable sandingtool comprising: a. a clam shell housing having a pair of housing halvesinterconnected to each other along a longitudinal split in said housing,b. an electric motor mounted in the housing, c. drive means mounted inthe housing To be powered by the motor, d. a pair of spaced recessesformed in each housing halve to extend transversely of the longitudinalsplit, e. each pair of recesses in one housing halve formed in alignmentwith the pair of recesses in the other housing halve, f. a plurality ofresilient posts adapted to extend from a position adjacent each cornerof the housing, g. a platen connected to each of the resilient posts,and operatively connected to be driven by the drive means, h. each ofthe resilient posts having an integrally formed flange extending apredetermined distance outwardly therefrom to define an end facethereon, and i. each flange insertable into one of the recesses of thehousing halves to be independently held therein and having the end faceof the flange extending toward the longitudinal split whereby onassembly of the housing halves the adjacent end faces to come intoengagement with each other forcing the resilient posts to be locked intotheir respective corner positions.